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Hello,

I am trying to solve the boundary value problem (1-x^2)*y'' - 2*x*y' +12*y = 0 with y(-1) = -1 and y(1) = 1.  I have not used Maple much, but from some web surfing, it seems like the following inputs should work:

de := (1-x^2)*(diff(y(x), `$`(x, 2)))-2*x*(diff(y(x), x))+12*y(x) = 0

Y := dsolve(de, y(-1) = -1, y(1) = 1)

However, when I input these lines, I get the error: Error(in dsolve), found wrong extra argument(s): y(-1) = -1, y(1) = 1

Does this mean that Maple can't solve this problem?  Is my syntax wrong?  I would appreciate any help.

 

Thanks!

Tim

 

Hello guys

I have a linear differentional equation which is in the 4th order. It is shown in the below:

P:=phi(x):
eq:=a11*diff(p,x,x,x,x)+a22*diff(p,x,x)+a33*p:
eq:=0:
where a11 and a22 and a33 are constant coefficients. The boundary value for this equation is:

phi(a)=sigma1 , phi(-a)=sigma1 , diff(p,x)(a)=0 , diff(p,x)=0

Now consider :

a11:=2.731e-10:
a22:=-1.651e-9:
a33:=3.09027e-10:
a:=35.714:
sigma1:=200e6:

when I use dsolve for deriving a good answer in this equation. there are four real roots .How can I solve it with these boundary condition?

I need to extract phi(x) from this equation.

Thanks

I have the following system I need to solve:

 

dy(t)/dt = alpha(t)-y(t)

alpha(t)=alpha0*(x(t)-x0)

dx(t)/dt=y(t)-beta(t)

beta(t)=beta0*(x(t)-x0)

 

 I am trying to get functions of y(t) and x(t), so I can plot y(t), x(t) and alpha(t) as it changes over time.

 

I have tried using dsolve to no effect.  I define the inital conditions, I define the functions I am looking for and when I press enter dsolve doesn't return anything.  I also know all the constants and defined them as well.

 

 

 

Thank you.

 

 

So I am brand new to using Maple and am trying to solve a system of ODE's. When I try and use dsolve however I reciever the error "function expected" and I am not sure why. The code I have is as follows

 

sys_ode := diff(A(t), t) = a*(A(t)+B(t))-b1*A(t)*(C(t)+D(t))-g1*A(t)*B(t), diff(B(t), t) = -b2*B(t)*(C(t)+D(t))+g1*A(t)*B(t), diff(C(t), t) = e*(b1*A(t)+b2*B(t))*C(t)-g2*b2*C(t)*B(t)-g3*C(t)*D(t), diff(D(t), t) = g2*b2*C(t)*D(t)-m*D(t)

dsolve([sys_ode])

 

I'm sure it is something simple, but I just can't seem to figure out where the issue is. Any help is much appreciated.

I am trying to recreate journal work for validating using another computer program so I am trying to use maple to solve the ODE, based on further research I found using laplace might be the best but I am having some trouble.

 

eq8:=d*(n(t)+C(t))/drho = -rho(t)/(l*alpha*K_c)

given the initial conditions of:

ICs:= n(0) = n_0, rho(0) = rho_0, C(0) = (beta-rho_0)*n_0/(l*lambda)

therefore: 

equation9 := dsolve({equation8, ICs}, {C(t), n(t)}, method = laplace)

 

Following this process I get the error: 

Error, (in dsolve) invalid initial condition

 

According to the journal work the solution I am looking for is: 

C(t)=-n(t)+(rho_0^2+rho(t)^2)/(2*l*alpha*K_c)+((Beta+l*lambda-rho_0)*n_0)/(l*lambda)

 

is there something that I'm doing wrong or missing? 

Any help would be greatly Appreciated! 

 

restart:

Eq2 := diff(T(y), y, y)+(diff(sigma(y), y))*(diff(T(y), y))+(diff(T(y), y))^2+(exp(-y)

+exp(y))^2 = 0;

Eq3 := diff(sigma(y), y, y)+(diff(T(y), y, y))= 0;

bcs2:=T(h1)=0,T(h2)=1,sigma(h1)=0,sigma(h2)=1;

dsolve({Eq2,Eq3,bcs2});

This give me nothing. Please help me out. 

 

 

restart;
ode := (-6 + 3*x - 3*x^2 + 2*x^3)*y(x) + x*(6 - 3*x + x^3)*diff(y(x),x) + x^2*(-3 + 3*x - 3*x^2 + x^3)*diff(y(x),x$2)= 0;
ic := y(0)= 0, D(y)(0)= 1:
sol:=dsolve({ode, ic},y(x));

Gives

 

What is _C2  that shows up there? Since this is second order and I give 2 initial conditions, I did not expect to see any _C in solution.  How should I handle this solution now? (say to evaluate it, etc...) with this unknown _C2 in there?

Maple 18.1 on windows.

hi..i am a problem with solving following ....please help me ....thanks alot

dsys3 := {10*f2(x)+12*(diff(f1(x), x))+14*f3(x) = 0, 2*(diff(f1(x), x, x))+4*(diff(f2(x), x))+6*(diff(f3(x), x)) = 0, 16*(diff(f3(x), x, x, x, x))+19*(diff(f3(x), x, x))+22*(diff(f1(x), x))+25*f2(x)+27*f3(x)+29*f3(x)+31+32 = 0, f1(0) = 0, f1(1) = 0, f2(0) = 0, f2(1) = 0, f3(0) = 0, f3(1) = 0, ((D@@1)(f1))(0) = 0, ((D@@1)(f1))(1) = 0, ((D@@1)(f2))(0) = 0, ((D@@1)(f2))(1) = 0, ((D@@1)(f3))(0) = 0, ((D@@1)(f3))(1) = 0}; dsol5 := dsolve(dsys3, 'maxmesh' = 500, numeric, range = 0 .. 1, abserr = .1, output = listprocedure); fy3 := eval(f3(x), dsol5); fy2 := eval(f2(x), dsol5); fy1 := eval(f1(x), dsol5)

ERROR.mw

hi.i am a problem with following dsolve.please help me....thanks alot

dsys3 := {10*f2(x)+12*(diff(f1(x), x))+14*f3(x) = 0, 2*(diff(f1(x), x, x))+4*(diff(f2(x), x))+6*(diff(f3(x), x)) = 0, 16*(diff(f3(x), x, x, x, x))+19*(diff(f3(x), x, x))+22*(diff(f1(x), x))+25*f2(x)+27*f3(x)+29*f3(x)+31+32 = 0, f1(0) = 0, f1(1) = 0, f2(0) = 0, f2(1) = 0, f3(0) = 0, f3(1) = 0, ((D@@1)(f1))(0) = 0, ((D@@1)(f1))(1) = 0, ((D@@1)(f2))(0) = 0, ((D@@1)(f2))(1) = 0, ((D@@1)(f3))(0) = 0, ((D@@1)(f3))(1) = 0}; dsol5 := dsolve(dsys3, 'maxmesh' = 500, numeric, range = 0 .. 1, abserr = .1, output = listprocedure); fy3 := eval(f3(x), dsol5); fy2 := eval(f2(x), dsol5); fy1 := eval(f1(x), dsol5)ERROR.mw

I got a problem with a difficult ode,the commands are below.

restart;
sys := 1.*(diff(x(t), t, t)) = piecewise(b(t) = 1, 0, 1003.0-1000.*x(t)-30.*(diff(x(t), t))-25.*signum(diff(x(t), t)-.1)-.3*signum(diff(x(t), t))*exp(-2*abs(diff(x(t), t)))), x(0) = 1, (D(x))(0) = 0;
mu := 100;
stick := [diff(x(t), t) = .1, b(t) = piecewise((1000.-1000.*x(t))^2 < 10000, 1, 0)];
slip := [[0, 10000 < (1000.-1000.*x(t))^2], b(t) = 0];
sol:=dsolve({sys,b(0)=0},numeric,discrete_variables=[b(t)::float],events=[stick,slip],event_maxiter=1000000,output=listprocedure,maxfun=0,range=0..8);

any advice is appreciated.

I got a problem in using dsolve.
In my real question, some functions are quite complicated.
so here is a simple example.
F1:=x(t)^2;F2:=piecewise(t>=0,y(t)^3,t>=0.1,exp(y(t)));
eq1:=diff(x(t),t$2)=F1;eq2:=diff(y(t),t$2)=subs(x=y,F1)-F2;
ic1:=x(0)=1.2,D(x)(0)=0;ic2:=y(0)=MM(tf),D(y)(0)=NN(tf);
#tf is the point where x(tf)=30.
dsolve({eq1,eq2,ic1,ic2,x(tf)=30},numeric);

above command can't give an answer.

how to use dsolve solve this problem?

any ideas is appreciated.

I'm trying to solve this system of ODEs by Laplace transform. 

> de1 := d^2*y(t)/dt^2 = y(t)+3*x(t)

> de2 := d^2*x(t)/dt^2 = 4*y(t)-4*exp(t)

with initial conditions 

> ICs := y(0) = 2, (D(y))(0) = 3, x(0) = 1, (D(x))(0) = 2

 

Using 

> deqns := de1, de2

and

> var := y(t), x(t)

 

I need to solve it for both y(t) and x(t), I have tried this by:

> dsolve({ICs, deqns}, var, method = laplace)

And

> dsolve({ICs, deqns}, y(t), method = laplace)

> dsolve({ICs, deqns}, x(t), method = laplace)

 

However I get this error message:

Error, (in dsolve/process_input) invalid initial condition

 

Any help is appreciated

Hello,

 

could you help me solve this error ? I don't understand what it means.

 


> eq3:=diff(x(t),t,t)+Gamma*diff(x(t),t)+omega[0]^2*(x(t)-(diff(x(t),t,t)+Gamma*diff(x(t),t)+omega[0]^2*x(t)+omega[0]^2*X[0])/omega[0]^2) = -omega[0]^2*X[0]:
> dsolve(eq3);
Warning, it is required that the numerator of the given ODE depends on the highest derivative. Returning NULL.

 

Thanks.

question: solve the direction field and curve that passes through each of indicated points.use different colours.

2)dy/dx=e^(-0.01xy^2)

(a) y(-6)=0

(b) y(0)=1

(c) y(0)=-4

(d) y(8)=-4

my answer:

> restart;
> with(DEtools);
> with(plots);
> a := diff(y(x), x) = exp(-0.1e-1*x*y(x)^2);
> g := dfieldplot(a, y(x), x = -8 .. 8, y(x) = -8 .. 8, color = exp(-0.1e-1*x*y(x)^2));

> ode := diff(y(x), x) = exp(-0.1e-1*x*y(x)^2);


> ics := y(0) = 1;
> dsolve({ics, ode});
  

it doesn't solve the ics n ode. actually i don't understand at all about dsolve bcoz this relating to exponential.

please do help me.thank you

 

btw before this someone do help me to solve my problem with this..here comes another problem..*sigh... thank you

Hello everybody. I'm newbie and my english are not very good. Please help me debug an error in my files DSOLVE_NOT_SUCCESSFULL.zip: "Error, (in ans) cannot determine if this expression is true or false"
Thanks.

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